Ergonomic core drilling system shoe interface

ABSTRACT

A shoe assembly of a core drilling system includes a lower tubular body threaded onto an upper shoe component, the shoe assembly in turn removably threaded on to an annular inner pipe integral to the earth core drilling system, the lower shoe having a torque pattern of two or more surface indentations or slots disposed strategically about the outer periphery thereof, the torque pattern matching a pattern of protrusive elements on a friction-breaking socket tool, wherein a worker may place the friction-breaking socket tool on or over the lower tubular body and use that tool to break the threaded interface between the upper shoe component and the inner pipe of the core drilling system and unscrew the shoe assembly from the inner pipe to remove an earth core sample from the inner tube pipe and to screw the shoe assembly back on to the inner tube pipe.

CROSS-REFERENCE TO RELATED DOCUMENTS

N/A

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention is in the field of resource exploration coredrilling systems leveraged to locate natural resources by creatingretrievable cores of earth that may be accessed and checked for thepresence of the desired resources in the field, pertaining particularlyto an ergonomic shoe interface and method including apparatus forbreaking the interface and restoring the interface in the field.

2. Discussion of the State of the Art

Within the field of earth exploration for natural resources scientistsand prospectors often require physical core-samples to be extracted fromthe earth using core drilling equipment. Typical core drilling systemsemploy a rotating open-ended core bit rigidly joined to a pipe called acore barrel. In general practice, the rotating bit cuts a cylindricalelongated core sample of earth aided by downward penetration forcethrough a drill string and fluid discharge. A stationary center coreresulting from the drilling process may be retrieved by an inner pipelatched to a wire line, the pipe sliding down about the cylindricalcore.

The far end of a core-capture inner pipe is referenced in the art as ashoe, typically an interface of two or more relatively heavy pipecomponents threaded together. The primary function of the shoe is tohold core breaking and retaining mechanisms. The lower shoe of the shoeinterface being slightly larger in diameter than the upper shoe. Thelower shoe hosting the core breaking apparatus and the upper shoecomponent of the interface hosting core holding or retaining apparatusreferred to as basket catchers but not limited to basket catchers perse. Typically the lower shoe is fastened to an upper shoe by a threadedconnection, which aids in assembly, and manufacturing time to machineseats, flanges, and mounts which hold and position basket-catchers, corebreakers, and other core breaking/retaining mechanisms. However, somesystems use a single shoe-body shoe, utilizing spacers or flanges tohold the core breakers, and potentially basket catchers and/or othercore breaking or retaining mechanisms dependent on the type of earthformation being cored. For example, in loose sand, some systems mayclose completely around the core sample bottom after separation of thesample from the earth. In some embodiments, there could be a middle shoeor multiple middle shoe segments which also hold different core breakingor retention mechanisms.

The inside of the shoe interface may serve multiple functions includingholding and positioning core breakers and holding basket catchers. Thelower shoe on its outside may function as a pressure nozzle for fluidfrom a pump to both lubricate the core bit of the core barrel, and, inone embodiment help remove earth cuttings with hydraulic pressure.Hydraulic pressure which discharges within the core bit, and around theoutside of the lower shoe assembly can act partially as the core cuttingmechanism cutting core from the earth with hydraulic pressure. This maybe somewhat dependent on the specific earth formation beingcore-drilled.

An adjustable lead screw mechanism facilitates the vertical distancebetween the lower shoe and the core bit for user control of thehydraulic pressure at the bit. The shoe interface has at least a lowershoe, but in practice typically contains two parts, generally the upperand lower shoe portions as described above. The upper shoe portion holdsannular/radially aligned biased springs known in the art as basketcatchers, the lower shoe portion typically holds and positions themovement of the core spring-breakers on their interior diameters. Thelower shoe portion has an outside diameter larger than the upper shoeportion or the inner tube to help stabilize the inner tube pipeassembly. Middle shoes can be employed to hold other core breaking andretaining mechanisms, however, this is not typical. The shoe portionsmay be connected together to form the shoe interface (assembly). A stepdown function on the free end of the lower shoe component of the shoeassembly functions to focus pressurized fluid discharge.

The inner tube pipe is typically suspended on a bearing apparatus thathangs within the larger diameter core barrel. The core bit at the end ofthe core barrel typically includes an internal polygonal inside-diameterstructure, the vertices thereof enabling fluid to pass around the shoeassembly to the core bit. The flats of the polygonal feature or othergeometric form coupled with the larger inside diameter of the lower shoefunction to keep the inner tube assembly from tilting or yawing. Aninner tube assembly is retrieved with a core sample inside and is thenlaid horizontally such as on a workbench where a worker or workersproceed to disassemble the inner tube assembly to extract the capturedcore sample.

A challenge with this process is the difficulty relative to breaking thethreaded interface that the shoe interface has with the inner tube pipe.During exploration drilling, many inner tube assemblies containing coresamples up to three meters, or more, in length are retrieved and stackedfor dis-assembly, core extraction, and reassembly. Six and nine meterlength inner tube pipes, within the inner tube assembly are not unheardof. Typical workflow per bench line worker or pair of workers may be toextract 20 to 80 sample cores per day, with one worker typicallythreading and rethreading the shoe 40 to 160 times a day, sometimesunder harsh on-site conditions such as extreme cold or hot weather,humidity, dirt, mud, and/or tar-saturated environments. Workers mayendure 12 hour shifts consecutively for up to 26 days.

Typically core breakers are housed in the lower shoe due to theirdurability, and proximity to the bit, and thereby the lowest extent of adrilled center core. The core breakers are an open-sided conical springsteel piece with a smooth exterior and a barbed interior. As the drillstring moves relatively upward, the core breakers slide down the taperedhousing and contract to grip, and ultimately break the core from theearth. The purpose of the core breakers, and in general allcore-retaining mechanisms, is to couple/lock the core to the shoe.Depending on the earth formation the core breakers may requiresignificant force to break the core, and can become wedged andfrictionally locked into the lower shoe. The unexpected, or unplannedfor, result of utilizing core breakers to break the core from the earth,is that workers when disassembling the shoe must also break the frictionconnection between the core breakers and the lower shoe, or otherwisemany times spin the shoe and the core, to remove the shoe. In somecases, the core weighs up to 100 pounds in rock formations. A worker ontop of spinning off a fine threaded shoe may also be required tomanually spin the core sample which is friction-locked to the corebreakers, and thereby the shoe.

In addition to the challenges of increased friction forshoe-disassembly, the position of the workpiece and movements, includingstance required by the bench workers in removing shoe assemblies fromthe inner pipes can be awkward for the worker and can cause strain orinjury. Core drilling rigs generally use mobile workstations which aretransported by helicopters, transfer trucks, or tracked vehicles, andtherefore are confined to a small and quickly assembled workspace. Theunintended consequence of designing confined work space is that the vicewhich holds the inner tube stationary may be positioned against a wall,on top of a bench, or against a railing, which may obstruct fullrotation of a pipe wrench, additionally rig design is expensive andgenerally cannot be modified in the field. Once the thread lock isbroken using a conventional pipe wrench, workers unthread the shoeassembly manually and may need to bend their wrists, or position theirbodies in an awkward stance to manually unthread the shoe.

Many bench workers develop minor to severe carpal tunnel syndrome,tendonitis and crepitus, often interrupting sleep patterns, causing painor discomfort requiring medication and eventually corrective surgery. Ascarpal tunnel syndromes, tendonitis, and crepitus are generally lessvisible negative safety outcomes on core drilling job-sites, and onlyappear after hundreds, or thousands or repetitions of moving a load,(generally with the wrist bearing the load) the extent of repetitivestress from removing a shoe interface from an inner tube pipe may not beobvious to safety managers, core drilling company owners, or rig tooldesign engineers.

Therefore, what is clearly needed is an ergonomically operable shoeinterface for a core drilling system and an apparatus that facilitatesergonomic removal and replacement of the interface or assembly in aproduction line.

BRIEF SUMMARY OF THE INVENTION

According to an embodiment of the present invention, a shoe assembly ofan earth core drilling system is provided and includes a lower annularshoe component threaded onto an upper annular shoe component, the shoeassembly may be removably threaded on to an annular inner tube pipeintegral to the earth core drilling system, the lower tubular bodyhaving a torque pattern of two or more surface indentations or slotsdisposed strategically about the outer periphery thereof, the torquepattern matching a pattern of protrusive elements on a friction-breakingsocket tool. In this embodiment a worker may place the friction-breakingsocket tool on or over the lower tubular body and use that tool to breakthe threaded interface between the upper shoe component and the innertube pipe of the core drilling system and unscrew the shoe assembly fromthe inner tube pipe to remove an earth core sample from the inner tubepipe and to screw the shoe assembly back on to the inner tube pipe.

In one embodiment, the two or more surface indentations comprising thetorque pattern are elongated slots parallel to one another, and alignedwith the longitudinal axis of the lower tubular body, and wherein thefriction-breaking tool is a socket tool with a handle and the matchingprotrusions are elongated keys that fit into the slots from the free endof the lower tubular body. In another embodiment, the surfaceindentations are blind seats linear in orientation, the torque patterndisposed orthogonally to the longitudinal axis of the lower tubular bodyaround the periphery thereof, and wherein the friction-breaking tool isa crescent tool having matching protrusions on the inside of a crescenthead, with the crescent head having a handle.

In a variation of the above slot embodiment, the torque pattern includesfive slots in a star pattern, accepting a matching star pattern of fiveelongated keys arrayed about the inside of the socket tool. In a furthervariation of the embodiment, the socket tool handle is a breaker barhandle. In yet another variation of the embodiment specifying slots asthe torque pattern, the socket tool handle is a ratchet handle.

In one embodiment of the present invention, the friction-breaking toolis a socket tool operated by a pneumatic system, an electric drivesystem, or a hydraulic drive system. In another variation of theembodiment specifying slot as the torque pattern, the slots extend atleast partially on to the peripheral surface of the upper shoecomponent, the threaded interface designed to align the slot patternswhen the components are fully threaded together.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an exploded view of an exemplary core drill system accordingto prior art.

FIG. 2A is a perspective view of a lower shoe of a shoe assemblymodified for ergonomic removal and replacement of the assembly relativeto an inner pipe according to an embodiment of the present invention.

FIG. 2B is an exploded view of a shoe assembly.

FIG. 3 is an end view of the lower shoe portion of the shoe assembly ofFIG. 2B.

FIG. 4 is a perspective view of the lower shoe of the shoe assembly ofFIG. 2B depicting core breaker apparatus.

FIG. 5 is a partial overhead view of a ratchet socket tool for breakingthe shoe assembly/inner pipe interface and for tightening the shoeinterface to the inner pipe.

FIG. 6 is a block diagram depicting an inner pipe with a shoe assemblyin position for core sample removal according to an embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

In various embodiments described in enabling detail herein, the inventorprovides a unique system for removing and replacing the shoe assemblyattached to an inner pipe of an earth core drilling apparatus. An objectof the invention is to reduce the manual labor currently required toremove and replace the shoe assembly, thereby reducing the potential forinjury to production bench workers performing the operation. The presentinvention is described using the following examples, which may describemore than one relevant embodiment falling within the scope of theinvention.

FIG. 1 is an exploded view of an exemplary core drill system 100according to prior art. Core drill system 100 includes a cylindricalcore barrel 101 having a heavy coring bit 103, and an inner tubeassemblyl02 designed to operate within core barrel 101 to slide over astationary core and separate a core sample for retrieval and analysis.Core barrel 101 is cylindrical and somewhat larger in diameter thaninner tube assembly 102 which is adapted to have an inside diameter thatmay slide over a stationary centered core sample produced by coring bit103. Inner tube assembly 102 has an outside diameter somewhat smallerthan the inside diameter of core barrel 101 to enable lowering of theinner tube assembly into the core barrel and retrieving the assemblyback out of the barrel. Inner tube assembly 102 fits into core barrel101 according to the direction of the depicted arrows. Inner tubeassembly 102 latches inside core barrel 101 prior to the drillingprocess via latch system 104 and machined feature 117 and anchor pointsor landing ring 116.

Inner tube assembly 102 includes all of the components needed to slidedown around a stationary core, and in conjunction with an upwardrelative force provided by the drilling rig to separate a measuredsection of that core, and retain the separated core sample sectionwithin the inner tube assembly. The inner tube assembly 102 can then beretrieved by wire line, using latch 115 for example, and an empty innertube assembly 102 may then be attached to the drill equipment wire lineand lowered back down into core barrel 101 to capture a next sample. Theinner tube assembly 102 may include a latching head section 115 at thetop interfacing with drill equipment suspending apparatus. Inner tubeassembly 102 may include a bearing 105 connected to a lead-screwmechanism 114 on top, and to an inner tube pipe section 106. Lead-screwmechanism 114 may hold a landing-nut 109 which, after lowering the innertube assembly into the core barrel, is suspended by the core barrellanding ring 116.

Inner tube pipe 106 may include a check valve 107, which may be a ballcheck valve. Inner tube assembly may further include a plastic pipelining pipe 108 adapted with an outside diameter just smaller than theinside diameter of the inner tube pipe 106. The inside diameter oflining pipe 108 is just large enough to slide over a stationary corewithout excessive play. The inner tube assembly may further include aplastic pipe lining pipe 108 adapted with an outside diameter justsmaller than the inside diameter of the inner tube pipe 106. Liner pipe108 slides up into inner tube pipe 106.

Inner tube assembly 102 includes a lower shoe 112 in the shoe assembly,the lower shoe 112 hosting a core breaking apparatus 113 (not visible).Lower tubular body 112 may be somewhat larger in outside diameter thanthe upper shoe component 111. Outside diameters of shoe components 112(lower shoe) and 111 (upper shoe) may vary according to a desired corediameter, which may range from one and one-half inches to several inchesin diameter depending on system and operation. A shoe assemblycontaining an upper shoe component 111 with a basket catcher apparatus110 is adapted to be installed (threaded) onto the lower end of innertube pipe 106. Basket catcher 110 seats within the inside diameter ofupper shoe component 111 and functions to retain hold of a separatedcore sample.

When assembled, the only visible parts of the inner pipe assembly 102are lower shoe component 112, upper shoe component 111, inner tube pipe106, rig-latching head 104, lead-screw mechanism 114, landing nut 109,bearing assembly 105, and the bearing crossover assembly 118. In theoperation of extracting core samples, connection between the upper shoecomponent 111 and the inner tube pipe 106 must be loosed and the shoethreaded off from the inner tube pipe 106. Inner tube pipe 106 hasexternal threads that match a female thread pattern on the inside topend of upper shoe component 111. To extract a core sample, the wholeshoe assembly must be removed from the inner pipe assembly 102 andreplaced once the core sample is removed from the inner pipe assembly.

FIG. 2A is a perspective view of a lower tubular body 112 modified forergonomic removal and replacement of a shoe assembly relative to aninner tube pipe according to an embodiment of the present invention.FIG. 2B is an exploded elevation view of the lower and upper shoecomponents and an inner tube pipe. Lower tubular body 112 is a heavythick-walled pipe that has a female pipe threading classified as a finethread pattern 202 on the inside diameter that accepts a male threadpattern on the external interfacing surface of the upper shoe component111 introduced above in FIG. 1. Inner tube pipe 106 (see FIG. 6) has amale external thread pattern on a thin wall pipe form which fits into afemale thread pattern on the inside diameter surface of the upper shoecomponent 111.

Referring now to FIG. 2B, shoe assembly 200 includes an upper shoecomponent 111 which has a relatively large diameter pipe and exists in afield where dirt, sand, grit and tar create friction between the shoeinterface and the inner tube pipe 106. Significant force may be requiredto break the friction lock of the mated threads to unscrew the shoeassembly from inner pipe 106. The external male threads on inner pipe106 are referenced herein as threads 207. The mating female threads onupper shoe component 111 are referenced herein as threads 209. In apreferred embodiment, it is desired that the shoe assembly 200 (lowertubular body 112 and upper shoe component 111) be unscrewed as a rigidtightly threaded (greater friction lock) assembly from the end of innertube pipe 106. In current art, the larger diameter of the lower tubularbody 112 prevents access by socket tool to the upper shoe component 111,which may have machined flats 208 provided thereon for seating a pipewrench.

The annular form of the shoe interface acts in conjunction withhydraulic fluid and the bearing assembly described in FIG. 1 above tominimize yaw and tilt of the inner pipe during drilling operationsmaking the provision of flats on the outside surface of the lower shoefor fitting a pipe wrench detrimental to the assembly.

Additionally, in many core drilled formations the pressurized hydraulicfluid discharging around the annular form of the lower shoe assembly mayplay an important role in cutting a cylindrical core from the earth andin cleaning the bit of certain types of core build ups. In particular ifthe inner tube assembly 102 tilts or yaws relative to the core barrel,core may jam and thereby plug the inner tube orifice prior to the end ofthe core drilling cut. Inner tube assembly yaw and tilt may also causethe inner tube assembly to be sheared into an ovular form, which canpotentially cause core slippage during wireline retrieval.

In the current art, a pipe wrench which grips on only two surfaces ofthe shoe assembly creates an increased risk of marring or ovalling ofthe shoe. On the outside diameter the shoe must remain annular due tothe tolerances with the rotating polygonal inside diameter shape of thecore bit, and also for even distribution of discharging hydraulic fluid.Discharging hydraulic fluid plays a crucial role within the lubricationof core entering into the inner tube assembly, cleaning the bit, and insome earth formations cutting the core with hydraulic pressure. Coredrillers may set and change the distance between the lower shoe and corebit using the lead screw mechanism 114 and landing nut 109 depending onwhich earth formation they are within, as fluid discharge pressure is akey parameter of core successful core drilling. Providing flats forfitting a wrench on lower tubular body 112 similar to flats 208 on uppershoe component 111 may be detrimental to the shoe assembly due to thepossibility of yaw, and uneven fluid discharge.

A consequence of utilizing tool steel dies to grip the shoe interface isthat a relatively softer material, perhaps 4140 molybdenum alloy steelmay be used for the shoes' bodies, which decreases the lifespan of theshoe assembly itself relative to harder materials; the threads wearingfaster, and the annular form becoming marred, or distorted quicker. Theuse of tool steel dies to grip the shoe relatively decreases thelifespan of the shoe's annular form, as the dies require slightdeformation of the surface of the shoe to grip it. Alternatively keys504 (of Fig.5) may use relatively softer material, such as brass,aluminum or copper to transfer torque to slots 203 (of FIG. 4), the keys504 being replaceable. Since the keys may be made out of a softermaterial than the shoe interface, the keys (504) wear instead of theshoe assembly.

Referring now back to FIG. 2A, in this embodiment, lower tubular body112 has a larger diameter then the upper shoe component (111, FIG. 2A)when threaded together due to the thicker wall. A substantial amount ofsurface material, perhaps half of the pipe thickness, may be removed bylathe from the outside surface of lower tubular body 112 forming astep-down feature 201 leaving a smaller concentric diameter 204extending to the end of the lower tubular body. At the free end of lowertubular body 112 the pipe thickness is machined to provide a taper downfeature 205. The pipe wall has greater thickness at the free end of thelower tubular body, the lower tubular body also presenting a smallerdiameter at the free end. The inside of the free end of the pipe has aninside taper producing a conical inside surface for hosting an internalcore breaker ring designed to help separate a core sample from astationary core resulting from drilling.

A plurality of elongated slots 203 are machined longitudinally along theoutside surface of lower tubular body 112 to form a torque pattern ofslots for securely seating a torque busting tool (not illustrated here)that may be attached to or otherwise fitted over the outside surface oflower tubular body 112. Such a tool may include a leverage handle orpneumatic power interface that can be used in place of a gripping pipewrench to break the thread lock so unscrewing the shoe assembly from theend of the inner pipe is possible without tool slippage that may mar theoutside surface of the pipe material. Electric and hydraulically poweredsocket tools may be used instead of a pneumatic tool without departingfrom the spirit and scope of the present invention.

In one embodiment, there may be two elongated parallel slots 203provided on opposite sides of lower tubular body 112. In otherembodiments, an equally spaced array of parallel slots 203 may present athree-slot pattern, a four-slot pattern, a star pattern (five slots) andso on. In alternative embodiments, slots 203 may be spaced unequallywithout departing from the spirit and scope of the invention. In thisembodiment, slots 203 break out of both ends of the thicker wall ofmaterial comprising the center portion of lower tubular body 112. Thatis not required in order to practice the invention as long as the slotpattern 203 breaks out to the free end of the pipe allowing a tool likea deep socket with a key pattern that matches the slot pattern to beplaced over the lower tubular body 112 from the free end wherein the keypattern engages the slot pattern 203. In this embodiment, slots 203break out of both ends of the thicker wall of material comprising thecenter portion of lower shoe. That is not required in order to practicethe invention as long as the slot pattern breaks out to the free end ofthe pipe allowing a tool like a deep socket with a key pattern thatmatches the slot pattern to be placed over the lower shoe from the freeend wherein the key pattern engages the slot pattern. In an alternativeembodiment, the lower tubular body does not include a step-down featurelike feature 204. In still another embodiment, the larger diameter pipeof the lower shoe and slots extend to the upper shoe, the threadsmachined to enable the slots of the upper shoe component 111 and thelower tubular body 112 to align.

In yet another embodiment only a lower shoe is used, in such anembodiment if basket catchers (110 of FIG. 1) are used they seat withinthe lower shoe. In yet another embodiment, slots extend from the lowershoe component 112 to the upper shoe 111 regardless of pipe diameter,the threads being machined to line up the slot pattern when assembled.

Referring now to FIG. 2B, inner tube pipe 106 includes male (external)thread pattern 207 on thin wall pipe which fits into female (internal)thread pattern 209 on upper shoe component 111. The components arealigned in the orientation of assembly as indicated by the directionalarrows.

FIG. 3 is an end view of the lower tubular body of FIG. 2A. In this viewlooking directly into the interfacing end of lower tubular body 112, itmay be seen that the torque pattern of slots 203 is a star pattern.Slots 203 have a key-way architecture having a width and a depth and arelatively flat floor. A key architecture for slots 203 is not requiredto practice the invention. Slots 203 may comply to a variety ofavailable geometric slot or keyway designs so long as the key apparatuson the torque busting tool engages the slot pattern 203 securely suchthat the tool does not come off or slip out of the slot pattern whenbeing used to break the friction lock of the threaded interface.

Step down surface 204 is preferably concentric with the outside diameterof lower tubular body 112. Wall 201 depicts the stepped down wallmarking the ends of slots 203. In one embodiment, a socket device may befabricated with a matching key pattern that may be slipped onto the freeend of lower shoe component 112 far enough along the longitudinal axisof the pipe material to engage the key pattern into the slot pattern. Asocket device may be fashioned to fit a breaker bar or sturdy ratchethandle functioning as a lever that may be operated to loosen theinterface between the shoe assembly and the inner tube pipe. Theinternal diameter of lower shoe component 112 has a conical taper in thewall thickness 301 to provide a seat for a core breaker apparatus (notillustrated). FIG. 4 is a perspective view of lower tubular body 112 ofFIG. 2A depicting a core breaker apparatus 113 introduced in FIG. 1above but not rendered visible in that Fig. Three slots 203 of a starpattern are visible in this perspective view. In this view, the free endof the lower shoe 112 is depicted in perspective and includes corebreaker apparatus 113 seated within the pipe form at an angle formed bythe conical taper feature described further above machined on the insideof the pipe. In this view, the slot pattern comprising slots 203terminates before breaking out at the interfacing end of the shoe. Threeslots of a star pattern are visible in this perspective view.

FIG. 5 is a partial overhead view of a socket tool 501 for breaking thethreaded interface between the shoe assembly (between the upper shoecomponent) and the inner tube pipe, and for force tightening the shoeinterface to the inner tube pipe. A socket tool 501 is provided in thisembodiment that includes a star pattern key array of key-ways 504 thatmay be manually slipped over the diameter of shoe component 112 and intothe slot pattern operating from the free end of lower tubular body 112.

Elongated keys 504 are square keys in this embodiment that have a widthdimension just smaller than the inside diameter of the slots. Socket 501may be modified at the back wall with a center opening that may fit asquare key of a breaker bar handle 502. In addition to a square key, anygeometric pattern may be used to couple a socket tool to a breaker bar.In this case a breaker bar (not pictured) may be leveraged by handle 502to break the thread lock keeping the shoe assembly and inner pipe 106tightly threaded together before the shoe assembly remaining fictionallyjoined may be removed from the inner tube pipe 106.

In one embodiment, the breaking tool is a ratchet tool having abi-directional ratchet disc 503, a drive square 505, and a handle 502allowing the socket tool 501 to be used entirely for screwing the shoeassembly on to the inner tube pipe. In one embodiment, the ratchet toolmay be a pneumatic tool that uses compressed air to spin the socket inthe two directions saving workers from manual threading operations whichmay be difficult with fine pipe threads that tend to become sticky orotherwise friction tight and resist movement, or may be friction lockedto the part or all of the 3m core sample by the result of drillingpractice and core breakers.

FIG. 6 is a block diagram 600 depicting an inner pipe with an intactshoe assembly in position for core sample removal according to anembodiment of the present invention. Inner tube pipe 106 containing acore sample for removal is placed horizontal onto a work bench 601 sobench line workers can remove the shoe assembly to retrieve the coresample. In this example, a vise apparatus 602 may be provided at the endof bench 601 and used to hold the inner tube pipe 106 in a fixed statepreventing the inner tube pipe 106 from rotating on the bench. In thisposition, lower tubular body 112 is suspended by vice 602 at the veryend of the workbench 601 so the free end is accessible to socket tool501 with handle 502. In one variant embodiment, the bench 601 extendspast the vice and could interfere with a breaker bar or a long handle.In such a case the socket tool may be operated by a pneumatic system, anelectric drive system, or a hydraulic drive system. With the use ofpneumatics, hydraulics or electric power, handle 502 may not bespecifically required to practice the invention.

A bench worker may place socket tool 501 over the free end of lowertubular body 112 from FIG. 4 in the direction of the arrow with the keypattern on the inside diameter of the socket tool 501 engaging the slotpattern 203 on the lower tubular body 112. In this position, inner tubepipe 106 is suspended by the vice at the very end of the workbench 601so the free end is accessible to socket tool 501. An additionalconfiguration may be provided by extending the step down feature to theupper shoe component. In another configuration, blind seats may be used.Handle 502 may be leveraged with relative minor force to unlock thethreaded interface between the shoe assembly and the inner pipe.

After the thread lock is overcome, rotation of the shoe assembly mayneed to overcome friction related to the core retention mechanisms andtheir friction lock to the core. A typical embodiment of the inventionuses a high torque mode, for example a breaker bar which leverages amanually produced force to break the initial thread lock. After the hightorque mode of the tool overcomes the initial high friction resistanceto rotation, typically the tool will use a high speed method ofrotation, for example a pneumatic, electric, or hydraulic drive whichspins a socket tool. An additional method of high speed rotation is touse a 90 degree handle attached to the breaker bar, offset and parallelto the longitudinal axis of the inner tube assembly which acts as acrank handle to spin the socket, and shoe interface. Within the methodof using a manual hand crank for high speed rotation, a segment of thebreaker bar can pivot 90 degrees to turn into a crank handle. The shoeassembly contains all of the components which host core retentionmechanisms, typically an upper and lower shoe, core breakers (113), andbasket-catchers (110). To break the friction lock of the shoe assemblythe shoe assembly must rotate relative to the inner tube pipe.

After the core sample is secured, the shoe assembly must be threadedback onto the inner tube pipe. The same tool may be used to re-threadthe shoe interface to the inner tube pipe, and then tighten the threadinterface with sufficient force to establish the friction-lock bottomingof the threads. To re-fasten the shoe interface typically the shoeassembly spins relative to a stationary inner tube pipe. Sand dirt andtar can contaminate the threads 207, and 209 (referring to FIG. 2b ). Toprevent thread damage a regulated pneumatic tool may be used, anelectric tool may be used with a known maximum torque output, or atorque limiter which limits the force applied to the threads may beused. When initially threading the shoe interface onto the stationaryinner tube pipe, the threads can become cross threaded, hence a workermay manually thread the shoe interface onto the inner tube pipe (106) byhand 1-2 turns to avoid cross threading, and then use the socket tool tospin the full length of threads to fully attach the shoe assembly to theinner tube pipe 106. In an embodiment two tools identical in nature canbe used, one driving the socket tool 501 (referring to FIG. 5)clockwise, and the other tool driving socket tool 501 counter clockwise.One tool of such a pair of tools may be dedicated to spinning the shoeassembly off, and the other tool of the pair to spinning the shoeassembly on. In a variation of this embodiment where two tools are useda torque limiter can be used when fastening the shoe interface to theinner tube pipe, to set the torque of the shoe to a measurable andcommon thread lock, to ensure the shoe is substantially friction lockedto the inner tube pipe for drilling. Conceptually it is possible to spinthe inner tube pipe, relative to a stationary shoe assembly using thesocket tool described to hold the shoe assembly stationary relative to aspinning inner tube pipe. It is also conceptually possible to spin boththe inner tube pipe and the shoe assembly in opposite directions toremove the shoe, and re-attach the shoe assembly using the keyed patternsocket to spin the shoe assembly.

In another embodiment of the present invention, automation may be usedto remove the shoe assembly after the friction lock of the threadedinterface is broken using the socket tool 501 and breaker handle 502. Inone embodiment, in place of elongated slots, blind seats may be placedaround the perimeter the lower tubular body, upper shoe component or anyplace on the shoe assembly wherein a breaker tool with a crescent headhaving matching protrusions may be placed orthogonally over the shoeassembly, provided that the seats are sufficiently far enough away fromthe free end of lower tubular body 112 to not impede stabilization, andfluid discharge. For example, an aircraft automation wrench tool that isessentially two motors that spins an open ended C-wrench.

In this embodiment, a worker may place the tool over the pipe engagingthe blind orthogonal seats (208) and then use a leveraged small amountof force to break the friction lock. Within embodiments using crescentheads which fit onto orthogonal blind seats (208), an off axispneumatic, electric or hydraulic gear system can be utilized to spin thecrescent head and thereby spin the shoe in two directions, relieving theworker of manually threading.

Occasionally core sticks out of the lower shoe a few inches, in suchcases a worker may break the core off using a hammer to allow a deepsocket tool with a key pattern to reach slot pattern 203, or use adeeper reach socket. However, in a variation of an embodiment whichworks around the occasionally problem of core sticking out of the innertube assembly mechanically, an open ended socket tool which slips overthe core-sample, utilizes a handle which acts as a breaker bar. In avariation of this embodiment the breaker bar may contain a motor or anoff axis power transmission, generally a ring gear, or pulley systemwhich is powered by pneumatics, hydraulics, which spins the open endedkey-pattern from its side. In another embodiment of the presentinvention, automation may be used to remove shoe assembly from the innertube pipe. In that embodiment, a machine may place the socket tool overthe shoe engaging the seats, or slots and may produce a leveraged forceto break the friction lock. A pneumatic, electric, or hydraulic drivensocket tool allows automation to perform all of the threading operationsrelieving the bench worker of threading by hand and therefore protectingthe worker from potential injury over time.

It will be apparent with skill in the art that the torque pattern andmatching tool of the present invention may be provided using some or allthe elements described herein. The arrangement of elements andfunctionality thereof relative to the invention is described indifferent embodiments each of which is an implementation of the presentinvention. While the uses and methods are described in enabling detailherein, it is to be noted that many alterations could be made in thedetails of the construction and the arrangement of the elements withoutdeparting from the spirit and scope of this invention. The presentinvention is limited only by the breadth of the claims below.

1. A shoe assembly of an earth core drilling system comprising: a lowertubular body having a first threaded connection to an inner tube pipe atone end, the inner tube pipe enabled to limit movement of at least onecore retaining mechanism within the inner tube pipe, the inner tube pipehaving a second threaded connection to an upper tubular body, the lowertubular body having a torque pattern of two or more surface indentionsor slots disposed strategically about an outer periphery, the torquepattern matching a pattern of protrusive elements on a friction-breakingannular tool; wherein the friction-breaking annular tool is enabled toencompass the lower tubular body to break the second threaded connectionand unthread the lower tubular body from the inner tube pipe, therebyremoving an earth core sample from the core retaining mechanism, and tothread the lower tubular body back on to the inner tube pipe and theupper tubular body.
 2. The shoe assembly of claim 1, wherein additionaltubular bodies may be threaded together to form a shoe assembly whichlimits the motion of at least one core retaining device.
 3. The shoeassembly of claim 1, wherein the two or more surface indentationscomprising the torque pattern are elongated slots parallel to oneanother and aligned with the longitudinal axis of the lower tubularbody, and wherein the friction breaking tool is a socket tool with ahandle and the matching protrusions are elongated keys that fit into theslots.
 4. The shoe assembly of claim 1, wherein the surface indentationsare blind seats linear in orientation, the torque pattern disposedorthogonally to the longitudinal axis of the tubular assembly bodyaround the periphery thereof, and wherein the friction-breaking tool isa crescent tool having matching protrusions on the inside of a crescenthead, the crescent head having a handle.
 5. The shoe assembly of claim3, wherein the torque pattern includes five slots in a star patternaccepting a matching star pattern of five elongated keys arrayed aboutthe inside of the socket tool.
 6. The shoe assembly of claim 3, whereinthe socket tool handle is a breaker bar handle.
 7. The shoe assembly ofclaim 3, wherein the socket tool handle is a ratchet handle.
 8. The shoeassembly of claim 3, wherein the friction breaking tool is a socket tooland the handle is replaced by a pneumatic system, an electric drivesystem, or a hydraulic drive system.
 9. The shoe assembly of claim 3,wherein the slots extend at least partially on to the peripheral surfaceof additional tubular bodies in the shoe assembly of claim 2, thethreaded interface designed to align the slot patterns when thecomponents are fully threaded together.
 10. A method of removing a coresample from an inner tube assembly including a lower tubular body havinga first connection to an inner tube pipe, the lower tubular body enabledto limit movement of at least one core retaining mechanism within theshoe comprising the steps of: securing the inner tube pipe in a viceapparatus on a surface; placing a friction-breaking annular tool havinga pattern of protrusive elements aligned to engage a torque pattern oftwo or more surface indentations or slots disposed strategically aboutan outer periphery of the lower tubular body; applying force to thefriction-breaking annular tool to break the second threaded connectionand unthread the lower tubular body from the inner tube pipe, therebyallowing for the removal of an earth core sample from the inner tubeassembly; utilizing the friction-breaking annular tool to thread thelower tubular body back on to the inner tube pipe.
 11. The method ofclaim 10, wherein additional tubular bodies are threaded together toform a shoe assembly which limits the motion of at least one coreretaining device.
 12. The method of claim 10, wherein the two or moresurface indentations comprising the torque pattern are elongated slotsparallel to one another and aligned with the longitudinal axis of thelower tubular body, and wherein the friction breaking tool is a sockettool with a handle and the matching protrusions are elongated keys thatfit into the slots.
 13. The method of claim 10, wherein the surfaceindentations are blind seats linear in orientation, the torque patterndisposed orthogonally to the longitudinal axis of the tubular assemblybody around the periphery thereof, and wherein the friction-breakingtool is a crescent tool having matching protrusions on the inside of acrescent head, the crescent head having a handle.
 14. The method ofclaim 12, wherein the torque pattern includes five slots in a starpattern accepting a matching star pattern of five elongated keys arrayedabout the inside of the socket tool.
 15. The method of claim 12, whereinthe socket tool handle is a breaker bar handlespec.
 16. The method ofclaim 12, wherein the socket tool handle is a ratchet handle.
 17. Themethod of claim 12, wherein the friction breaking tool is a socket tooland the handle is replaced by a pneumatic system, an electric drivesystem, or a hydraulic drive system.
 18. The method of claim 12, whereinthe slots extend at least partially on to the peripheral surface ofadditional tubular bodies in the shoe assembly of claim 2, the threadedinterface designed to align the slot patterns when the components arefully threaded together.